1. Field of the Invention
The present invention generally relates to apparatus, methods, and systems for treating stormwater, and, more particularly, to separating sand, oil, biomass, and other debris from water and reducing the amount of nutrients and nitrogen compounds in treated stormwater. More broadly, the present invention relates to apparatus, methods, and systems for treating high volumes of liquids, mixtures, suspensions and the like to separate them into constituent parts.
2. Relevant Background
Modern storm drainage systems involve directing stormwater to storm or sewer drains where the water is collected for later processing and disposal or simply discharged into larger bodies of water. In those systems, stormwater is guided to flow from slopes and streets into the storm drains by the force of gravity. During that flow, stormwater may pick up debris, trash (e.g., paper, cans, and cigarette butts), biomass (e.g., grass, leaves, excrement and discarded food), silt, sand, stone, oil, pollutants, heavy metals, and discarded medical devices and personal products (e.g., used needles and condoms) and other particles. Further, the storm drainage systems may also collect other run-off water such as water used for irrigation. Stormwater and run-off water may naturally flow through soil or other terrains and pick up organic matter or chemicals, such as plants, leaves, hydrocarbons, nitrates, or other compounds.
There is a great deal of interest in effectively processing stormwater. Drainage systems usually flow into natural water systems, such as oceans, lakes, rivers, streams, and other similar bodies of water. It would help protect the environment if there was a realistic, cost-effective capability to separate out man-made and natural contaminants and pollutants before the drainage is directed into the natural water systems and avoid upsetting the natural ecological balance of such systems. Further, if stormwater and other run-offs can be effectively treated and recaptured as clean water, or at least as gray water, there is a potential that the recaptured water can help satisfy domestic needs for water.
There is also considerable interest in treating fluids for mining, agriculture, and industrial use. Besides the treatment and purification of water, the products separated from the fluid during treatment may be of value. For example, minerals in run-offs from mining or farms that contain high nutrient contents, various constituents of lubricants, and the like may be separated, collected, and reused or recycled. Further, the recovery of fluids or solids in industrial applications and from waste streams may be of interest.
U.S. Pat. No. 7,311,818 to Gurfinkel discusses an approach to a water separation unit having an inner and outer housing for storm water collection. Storm water enters the inner housing where water and debris are supposed to be separated. A series of hollow tubes connect the inner housing to the outer housing to allow liquid to pass into and collect in the outer housing and flow out of the unit through a network of discharge pipes. One problem with that approach is that the tubes can be clogged with debris. Another problem with that approach is that most of the silt and sand is not collected at the tube level in the inner housing; rather, it flows through the tubes and can be drawn into the discharge pipe and exit the outer housing. Yet another problem with that approach is that the unit must be completely drained before cleaning.
U.S. Pat. No. 7,846,327 to Happel, commercialized as the Nutrient Separating Baffle Box from Suntree Technologies, discusses an approach to a storm water filter box having a fixed basket to collect debris and a floatable skimmer to prevent floating debris that passed through the basket from leaving the box. The skimmer is positioned within the box between the inlet and the outlet and rises and falls with the water level in the box. Storm water is directed to pass through the basket to the skimmer where floating debris is collected. One problem with that approach is that moving parts that can break or jam are required for the skimmer to move. Another problem is that floating debris stays in contact with the wastewater, promoting decomposition of the debris.
U.S. Pat. No. 7,857,966 to Duran discusses an approach to a storm water inlet apparatus having inlet and outlet pipes on level with each other where wastewater flows directly through a catch basin. The apparatus includes a hood and skirted boom affixed to an interior wall of the basin over the outlet pipe. Wastewater flows beneath the hood and skirted boom and out through the outlet. In the process, heavier-than-water sediments sinks to the bottom of the basin while lighter-than-water debris floats on top of the wastewater in the basin. One problem with that approach is that a sealed hood prevents airflow, allowing a siphon to develop and pull the level of the wastewater down and potentially draw in the floating debris, thus reducing the performance of the apparatus. Also, the debris stays in contact with the wastewater, promoting decomposition of the debris.
U.S. Pat. No. 7,780,855 to Eberly discusses an approach to a system for storm water treatment. A treatment unit is connected to a control chamber through which fluid flows. The fluid is diverted via a control partition to an inlet pipe into the unit for treatment and returned through an outlet pipe. If the fluid flow exceeds the capacity of the inlet pipe, excess fluid flows over the control partition to the outlet of the control chamber. A problem with the approach is that it is not well-suited for a retrofit application due to the lack of significant grade between the inlet and outlet of the control chamber. Another problem with that approach is that there is no separation between different types of debris, i.e. biomass, hydrocarbons, silt and sand, etc.; everything is mixed in a potentially toxic soup.
U.S. patent Ser. No. 10/430,170 to Peters et al. discusses a system for removing contaminants from storm water. Storm water flows through a process chamber comprising a series of vertical baffles that extend from the top, bottom, and sides of the chamber. Storm water flows through the chamber around the baffles, and debris is trapped along the bottom of the chamber and by filters placed in the gaps between the baffles and the chamber. One problem with that approach is that all filtration is done in the water; thus, debris stays in contact with the water promoting decomposition of the debris. A further problem with that approach is that all debris is collected at the bottom of the chamber, limiting the capacity of the chamber for collecting debris. Another problem with that approach is that the relatively small gaps between the baffles and the chamber may become easily clogged with debris.
There is further need for an efficient, cost-effective apparatus methods and systems for separating stormwater, operating fluids, lubricants, coolants, wastewater and the like to separate out solids, hydrocarbons, contaminants and pollutants, and recapture and recycle desired components.